Patent Document 1 discloses a technology that controls clutch connection to prevent hunting caused by a residual torsion of a driving system due to a rotational speed difference between a front wheel (left wheel) and a rear wheel (right wheel) during traveling of a vehicle.
Patent Document 2 discloses a technology that measures a rotational speed difference between a front wheel and a rear wheel in a four-wheel-drive vehicle having a device controlling distribution of a driving force to the front and rear wheels, and which prevents hunting of a control system which hunting occurs when the driving force distribution is realized by feedback of the rotational speed difference.